Pipe-type cable controller comprising self-testing features



J. L. LANSCH Sept. 6, 1966 PIPE-TYPE CABLE CONTROLLER COMPRISINGSELF-TESTING FEATURES 9 Sheets-Sheet 1 Original Filed July 25, 1960INVENTOR.

J' /wv 1. L4A/sch' hN g Sept. 6, 1966 J. L. LANSCH PIPE-TYPE CABLECONTROLLER COMPRISING SELF-TESTING FEATURES Original Filed July 25, 19609 Sheets-Sheet 2 L 0 P106 46/ H6 5/ m #7 (Ha 522/ JNVENTOR. fof/lv Lulvsa/ Sept. 6, 1966 J. L. LANSCH 3,

PIPE-TYPE CABLE CONTROLLER COMPRISING SELF-TESTING FEATURES OriginalFiled July 25, 1960 9 Sheets-Sheet 5 IN VEN TOR.

JOHN A. A/IMFC/l Sept. 6, 1966 Original Filed July 25, 1960 J. L. LANSCH3,271,752

PIPE-TYPE CABLE CONTROLLER COMPRISING SELF-TESTING FEATURES 9Sheets-Sheet 4 3 607 5&1

Q\ S, INVENTOR Sept. 6, 1966 J. 1.. LANSCH PIPE-TYPE CABLE CONTROLLERCOMPRISING SELF-TESTING FEATURES 9 Sheets-Sheet 5 Original Filed July25, 1960 J. L. LANSCH Sept. 6, 1966 PIPE-TYPE CABLE CONTROLLERCOMPRISING SELF-TESTING FEATURES a mm \m mi Original Filed July 25, 1960Sept. 6, 1966 .1. L. LANSCH 3,

PIPE-TYPE CABLE CONTROLLER COMPRISING SELF-TESTING FEATURES OriginalFiled July 25, 1960 9 Sheets-Sheet 7 RECORDER ,3 (Fig.5b)

479 TIMER 476 C 474 ,473 TERMINAL BLOCK TERMINAL BLOCK CONTROL PANEL 469ALARM PANEL 299, 301,302,303304505 30650 308509 F fg. 6 INVENTOR.

JOHN L. LANSCH Y Sept. 6, 1966 J. L. LANSCH 3,271,752

PIPE-TYPE CABLE CONTROLLER COMPRISING SELF-TESTING FEATURES OriginalFiled July 25, 1960 9 Sheets-Sheet 8 69621622 g 623 624 626 6%? a e 296% 632 (35 UTJF United States Patent 3,271 752 PIPE-TYPE CABLECONIROLLER COMPRISING SELF-TESTING FEATURES John L. Lansch, Nyack, N.Y.,assignor, by mesne assignments, to Anaconda Wire and Cable Company, acornoration of Delaware Original application July 25, 1960, Ser. No.45,115, new Patent No. 3,155,765, dated Nov. 3, 1964. Divided and thisapplication Oct. 1, 1964, Ser. No. 414,042

3 Claims. (Cl. 340-214) This application is a division of Patent No.3,155,765, issued Nov. 3, 1964.

My invention relates to apparatus for maintaining oil pressure in apipe-type cable system and particularly to such apparatus incorporatingautomatic switch-over de vices responsive to failures in the electric orhydraulic components of the system.

In pipe-type cables electrical conductors insulated for high voltageservice, by which I mean service at voltages usually above 15 kv. and ashigh or higher than 230 kv., are laid in a fluid-tight pipe which iskept filled with electrical insulating grade oil under pressure. Theinsulation used for pipe-type cable is almost universally a plurality oflayers of paper which is penetrated by the insulating oil. To achieveadequate dielectric strength while the cable is energized the insulatingoil is maintained at a high pressure which has become standardized atabout 200 p.-s.i.g. To maintain the purity of the oil it is also highlydesirable to maintain positive pressure in the line at all times eventhough the cable is inoperative. This pressure need not be as high asthe pressure maintained around the conductors when they are energizedand 1 prefer to keep a pressure of about 60 p.s.i.g. on the cable whenit is deenergized.

A pipe-type cable is usually an expensive engineering installationsupplying power to important industrial and utility systems where anyinterruption of service will involve large economic losses. I havetherefore incorporated in my apparatus alarms and automatic safeguardsto prevent minor irregularities in the system from progressing to thepoint of a power shutdown.

During normal operation of a pipe-type cable the oil in the pipe willexpand and contract periodically and provision must be made to store theexcess oil during periods of expansion, and to maintain adequatepressure during periods of contraction. The oil expands because it isheated either by transfer of heat from the electrical conductors whenthey are under load, or by transfer of heat through the pipe from theoutside surroundings.

To accommodate the excess oil during periods of expansion I haveprovided one or more reservoirs or tanks connected by means of a novelcombination of piping and check valves, and mechanical and magneticrelief valves tho :the pipe-(type cable. To maintain pressure in thepipetype cable during periods of contraction of the oil I have providedone or more controllers, each incorporating a pump for returning oilfrom the reservoir into a pipe-type cable. Although I prefer to usepumps to build up oil pressure it will be understood that other pressuremeans such as pressure supplied from gas cylinders, may also be used.

I have provided a novel combination of controls and local and remotealarms, said controls and alarms being controlled by a plurality ofrelays. Said relays, in my invention, are of an interchangeable, plug-intype whereby any relay failure may be immediately corrected by theinsertion of :a spare relay for which I have provided a specialreceptacle to replace the faulty member. I have also provided a novelbuilt-in means for testing the circuitry of my apparatus withoutinterrupting the operation thereof and without setting off any remotefalse alarms.

I have provided my apparatus with means whereby,

when a plurality of pumps are used, failure or inadequacy of one pump tomaintain pressure in an associated portion of the system willautomatically open connectors to the output from on adjacent pump and Ihave also provided that this automatic cross over shall take place onlyduring operation of the pipe-type cable at normal pressure.

I have provided my apparatus with a novel combination of mechanical andmagnetic relief valves whereby I am able \to control the pressure in apipe type cable within much closer limits than has heretofore beenpracticable.

I have pmovided .my system with means whereby upon failure of a normalsource of power the apparatus will switch over no an auxiliary source,and I have also provided that such momentary interruptions of powershall not set off any remote alarms and that following a powerinterruption the system shall automatically resume [a type of operationwhereby it maintains the pipe-type cable at normal pressure.

Prior art devices for regulating the pressure in pipetype cables haveinvolved separate and distinct systems for control and for alarm. In mysystem. there is a close integration of the alarm and control functionwhereby the same relay that operates a control valve or other mechanismis interlocked with alarm circuits when necessary.

My system comprises novel interlocking circuitry whereby only certainsequences of operations which may be known only to selected authorizedpersons may be followed to change to reduced pressure operation or tochange from manual to automatic controls.

I have further provided that connection between the operating elementsof my system and the control panels shall be made by means of aplurality of plugs and matching receptacles whereby it is possible toisolate sections of the system for the purpose of making changes orrepairs. In addition I have provided an interlock which will show analarm when any of the aforementioned plugs are not connected to theirreceptacles.

Means are prow'ded in my apparatus to maintain pumping actions untilpressure has risen at the remote ends of the pipe-type cable and to showan alarm for excessive cycling or failure of pumping action to reach therequired pressure within a reasonable time.

I have incorporated in my system novel means for simultaneously testingall the signal lamps including the lamps in the control circuits withoutat the same time interrupting the normal operation of my apparatus.

Further advantages and objects of my invention will be made apparent byconsideration of the appended drawings and the detailed descriptionsthereof.

In the drawings:

FIG. 1 is a schematic diagram of the apparatus and pip ing of oneembodiment of my invention.

FIG. 2 is a wiring diagram of the power transfer switch of oneembodiment of my invention.

FIG. 3 is a wiring diagram of the main power circuit breaker and motorstarter for the pump of my invention.

FIGS. 4a and 4b combined are a wiring diagram of a portion of theapparatus of my invention.

FIGS. 5a and 5b combined are a wiring diagram of another portion of theapparatus of my invention.

FIG. 6 is a block diagram of a feature of my invention.

FIG. 7 is a perspective view of a test. unit of my invention.

FIG. 8 is a wiring diagram of a test unit of my invention.

Referring to FIGURE 1 twin controllers designated generally 11, 11amounting high pressure pumps 13, 13a are connected through pipe lines14, 14a to a pipe-type cable, not shown, within which it is desired tomaintain oil at an elevated pressure, such as a pressure of 200 p.s.i.g.It is required that this pressure shall be main tained in the "systemwithin a narrow range notwithstanding changes in temperature causingexpansion and contraction in the oil, or slow leaks r seepage of oilfrom the system. It is also required that appropriate alarms be given atthe controllers and possibly at one or more remote stations in the eventof a large leak or of loss of power to the pumps 13, 13a or otheremergencies as shall be hereinafter described.

I have shown the twin controllers 11, 11a associated with pipe lines 14,14a but a single controller such as 11a may be used for a pipe-typecable system not large enough to require twin controllers. Where twincontrollers are used they may be installed at a joint in a relativelylong pipe-type cable with the pipe line 14 connected to the pipe-typecable on one side of the joint and the pipe line 14a connected to thesame pipe-type cable at the other side of the joint.

The pipe lines 14 and 14a for which I prefer to use 2- inch steel pipe,are joined at a normally closed manual stop valve 15 and flow throughthe lines can be controlled by a pair of normally open manual valves 16,16a downstream and 17, 17a upstream of a pair of cross couplings 18,18a. A pair of normally closed manual valves 19, 19a each seal off oneleg of the cross couplings 18, 18a affording provision for possiblefuture connections.

I prefer to assemble certain valves and other equipment to be describedin a trench 20 from which pipe connections are made to the controllers11, 11a through 0- ring sealed unions 21, 21a, 22, 22a and 23, 23a.

The upstream sides of the valves 17, 17a are joined through Ts 24, 24aand the unions 22, 22a to the pipe lines 26, 26a controlled by normallyopen manual stop valves 27, 27a. Within the trench 20 I have laid thepipe lines 28, 28a connecting respectively, the Ts 24, 24a to the unions23, 23a. Check valves 29, 29a in lines 28, 28a prevent flow in saidlines back from the Ts 24, 24a.

Connecting the pipe lines 28, 28a, I have placed a crossover systemcomprising check valves 31 and 32, normally closed magnetic reliefvalves 33 and 34 and normally open manual stop valves 36 and 37; also inthe trench 20 I have included a pipe line 38, 38a connected to the oilstorage reservoir system generally designated by the numeral 39. Theline 38, 38a is connected to the controllers 11, 11a through the unions21, 21a respectively under the control of normally open manual stopvalves 41, 41a. Entry to an oil storage tank 42 takes place through twoTs 43, 43a in the pipe lines 38, 38a isolated by a normally closed stopvalve 44. Entry into the tank 42 is further controlled by normally openmanual stop valves 46, 46a.

The oil tank 42 is equipped with an oil level indicator alarm 47 and anoil drain controlled by a normally closed manual stop valve 48. Athermostat 49 has been located on the controller 11 but may be placed atany convenient location in the pump room. A cylinder 50 of dry inert gasof which nitrogen is a preferred example provides an inert atmosphere tothe tank 42 through the pipe line 51 having normally open manual stopvalves 52, 53, 54 and 56. The pipe line 51 for which I prefer to usehalf-inch copper piping is connected to a safety vent 57 through anormally closed manual stop valve 58. The vent 57 is connected to theoil tank 42 through a safety head diaphragm 59. A manhole 61 providesentrance to the tank 42 for the purpose of cleaning.

The cylinder 50 is equipped with a regulator 62 connected by means ofthe flexible hose 63 and normally open manual stop valve 64 to the pipeline 51. The valve 56 is located in the controller 11a which alsocontains a pressure alarm 66 and pressure gauge 67 connected to the pipeline 51. Oil leaving the tank 42 enters through the pipe lines 38, 38aand the unions 21, 21a through normally open manual stop valves 68, 68ainto the pumps 13, 13a. The pumps 13, 13a force the oil from the storagetank 42 through check valves 69, 69a, normally open manual stop valves71, 71a and 72, 72a and the valves 29, 29a, 17, 17a and 16, 16a into thepipe-type cable.

A return oil circuit between the tank 42 and the pipetype cable isprovided through the pipe line 14, the valves 16, 16a, the crosscouplings 18, 18a, the valves 17, 17a, the Ts 24, 24a, the unions 22,224, the valves 27, 27a, the pipe lines 26, 26a, the Ts 73, 73a, 74,74a, 76, 76a, 77, 77a through strainers 78, 78a, normally open magneticrelief valves 79, 79a, normally closed mechanical relief valves 81, 81a,normally open manual stop valves 82, 82a, Ts 83, 83a, 84, 84a, 86, 86a,normally open manual stop valves 87, 87a, the unions 21, 21a, the pipelines 38, 38a, the valves 41, 41a and 46, 46a. The valves 81, 81a areclosed until the pressure in the oil reaches some predetermined valuewhich I prefer should be 225 p.s.i.g.

A pair of valves parallel to the valves 81, 81a and 82, 8211 areprovided by normally closed mechanical relief valves 88, 88a andnormally open manual stop valves 89, 89a. I prefer to have the valves88, 88a set to open at a pressure of 250 p.s.i.g. Valves 90, 90a arenormally closed manual valves closing a circuit parallel to the circuitsprovided through the valves 81, 82 (81a, 82a) and 88, 89 (88a, 89a).Parallel to the lines comprising respectively the strainers 78, 78a, thevalves 88, 88a, 79, 79a, 81, 81a, 89, 89a and 82, 82a are linesconnected to the Ts 74, 74a including normally closed magnetic reliefvalves 91, 91a, check valves 92, 92a, and normally open manual stopvalves 93, 93a. The magnetic relief valves 91, 91a are automaticallyopened at a predetermind pressure which I prefer should be 300 p.s.i.g.by means of a control circuit hereinafter to be described.

From the foregoing it will be evident that the mechanical valves 81,81a, 88, 88a and the magnetic valves 91, 91a provide stepped means forrelieving pressure transmitted from the pipe-type cable to the pipelines 14, 14a by releasing oil into the tank 42. A further safeguardcomprises built-in spring-loaded relief valves 95, 95a in the pumps 13,13a. I prefer to use valves which will release when the pressure in thepumps reaches a value of 375 p.s.i.g.

The controllers 11, 11a contain oil pressure recorder and control units94, 94a for which I prefer to use Foxboro Standard Recorders with dualrotax units such as number 77SDX77-799 special for 24-volt D.C. service,supplied by the Foxboro Company.

Each of the units 94, 94a includes two pressure actuated contact deviceshereinafter to be described. The left-hand of said devices is connectedthrough the pressure piping 96, 96a, normally open instrument stopvalves 97, 97a, 98, 98a, unions 22, 22a, Ts 24, 24a and pipe lines 14,14a to the pipe-type cable. On the same pipe lines 96, 96a separated bynormally open instrument stop valves 99, 99a are oil pressure gauges101, 101a. It will be seen that the pressure in the left-hand devices ofthe units '94, 94a and in the oil pressure gauges 101, 101a beingapproximately equal to the pressure in the pipe-type cable. Theleft-hand devices may be used to actuate the automatic controls for thecable system.

The right hand devices of the units 94, 94a are connected throughpressure piping 102, 10 2a, normally open instrument stop valves 103,103a and 104, 104a to the discharge side of the pumps 13, 13a. Normallyclosed instrument stop valves 106, 106a separate the left hand piping96, 96a from the right hand piping 102, 102a. The right hand devices areused to control the pumps 13, 13a.

In the event of damage to either of the pumps 13 or 13a said pumps canbe isolated by closing the respective valves 68, 68a without interferingwith the operation of the automatic controls actuated by oil pressure inthe piping 96, 96a.

The piping of the controllers 11, 11a is interrelated in the mannerhereinbefore described, the circuitry of the controller 11 ispractically identical to the circuitry of controller 11a, so that theoperation of only controller 11 will be described, with theunderstanding that the operation of controller 11a is, for the purposeof this application, practically identical.

Referring to FIGURE 2, power for the operation of the controller 11 andauxiliary equipment is received from a 3-phase normal supply system 111which may conveniently be 208 volts phase-to-phase but may have othervoltage values such as 220, 230, 240, and 440 volts. Power for theoperation of my system can also be received from an emergency supply 112having the same characteristics as the normal supply 111. Power from thenormal supply 111 is fed to a main circuit breaker 113 through a 3-polemagnetic switch 114 actuated by a coil 116. Power from the emergencysupply 112 is fed to the main circuit breaker 113 through a 3-polemagnetic switch 117 actuated by a coil 118. Switches 114 and 117 aremechanically interlocked by a known mechanism indicated by the dashedline 115 in such a manner that both the switches 114 and 117 may be openat the same time, either may be open with the other closed, but both ofthe switches 114 and 117 cannot be closed at the same time.

A 4-po1e transfer relay 119 is actuated by a coil 121. The relay 119comprises two normally closed switches 122, 123 and two normally openswitches 124, 126.

The normally closed switch 122 of the relay 119 has one terminalconnected with a terminal of the normally open switch 126. The normallyopen switch 124 has one terminal connected through the coil 116 with aphase 127 of the normal supply 111. The other terminal of the switch 124is connected with a phase 128 of the normal supply 111 and is alsoconnected through the coil 121 with the phase 127 of the normal supply111. One terminal of the switch 123 is connected through an on-offswitch 129 through the coil 118 with a phase 131 of the emergency supply112. The other terminal of the switch 123 is connected with a phase 132of the emergency supply 112. From the foregoing it will be apparent thatwhen the normal power supply is energized current will pass through thecoil 121 closing the switches 124, 126 which in turn will activate thecoil 116 closing the power switch 114 so that the current from thenormal supply can flow to the main circuit breaker 113. In the event offailure of the normal supply 111 the relay 119 will act to close theswitch 123 thus energizing the coil 118 and closing the switch 117 tosupply current from the emergency supply 112 to the main circuit breaker113.

I have shown the normal power supply 111 and the emergency power supply112 for my controller 11. It is advantageous to wire my controller 11ain such a manner that it will employ the supply 112 as a normal supplyand the supply 111 as an emergency supply. Thus a dual controller systemwill in normal circumstances draw power from each of two sources ofsupply but continue to operate both controllers in the event of thefailure of either source.

The pump 13 (FIGS. 1 and 3) receives power through a magnetic motorstarter 133 (FIG. 3) actuated by the coil 134, which is in series withoverload switches 136. The starter 133 comprises, in addition to thethree phasecurrent switches 137, 138 139, a normally open auxiliaryswitch 141 and a normally closed auxiliary switch 142.

The coil 134 is connected by means of relays hereinafter to be describedbetween the phase 128 of the main circuit breaker 113 and ground.

Referring now to FIGURES 4a, 4b, 5a and 5b power for the operation ofthe controllers and their associated relays and alarms originates in asource of 120 volt A.C. made available through power lines 203 and 204of which the line 204 is grounded or may be an insulated neutral. Atransformer-rectifier 206 supplies 24 volt A.-C. to lines 207 and 208,24 volt D.-C. positive to a line 209, and 24 volt D.-C. negative to aline 210. The D.-C. voltage supplied from the lines 209, 210 serves toactivate the coils of three-pole double-throw relays 211 to 236inclusive.

It is a feature of my invention that the relays 211 to 236 are of theinterchangeable plug-in type. I have found that although all the polesare not invariably required such as is the case for the relay 226, itgreatly facilitates the economical operation of my system to utilizerelays which can be replaced by a standard spare and by a simpleplugging in operation. I have also provided my controller with testreceptacles 237 and 238 having contact points 237a-237k, and 238a238krespectively.

The left hand pressure device of the unit 94 which is activated by thepressure in the piping 96 shown in FIG. 1 comprises a plurality ofswitches which operate in response to the pressure of the oil in thepiping 96 in predetermined fashion according to principles that are wellknown. Accordingly a switch 241 will open when the pressure in thepiping 96 drops below 250 p.s.i.g. and will close when the pressurerises above 250 p.s.i.g.; a switch 242 will open when the pressure inthe piping 96 drops below 300 p.s.i.g. and will close when it risesabove 300 p.s.i.g. A switch 243 (FIG. 4a) will open when the pressuredrops below 260 p.s.i.g. and will close when the pressure rises above260 p.s.i.g.; a switch 244 will close when the pressure drops belowp.s.i.g. and will open when the pressure rises above 160 p.s.i.g.; aswitch 245 (FIG. 5b) will close when the pressure drops below 150p.s.i.g. and will open when the pressure rises above 150 p.s.i.g.; and aswitch 246 (FIG. 50!) will close when the pressure drops below 200p.s.i.g. and will open when the pressure rises above 200 p.s.i.g. in thepiping 96.

Similarly the right hand device in the unit 94 activated by the pressurein the piping 102 comprises an additional plurality of switches whichoperate in response to the pressure of the oil in the piping 102. Aswitch 247 (FIG. 5a) closes when the pressure in the piping 102 drops below 210 p.s.i.g. and opens when the pressure rises above 210 p.s.i.g.; aswitch 248 closes when the pressure drops below p.s.i.g. and opens whenthe pressure rises above 180 p.s.i.g.; a switch 249 closes when thepressure drops below 65 p.s.i.g. and opens when the pressure rises above65 p.s.i.g.; a switch 250 closes when the pressure drops below 45p.s.i.g. and opens when the pressure rises above 45 p.s.i.g.; a switch251 opens when the pressure drops below 60 p.s.i.g. and closes when thepressure rises above 60 p.s.i.g.; a switch 252 opens when the pressuredrops below 75 p.s.i.g. and closes when the pressure rises above 75p.s.i.g.

One terminal of each of the switches 241 through 252 is connectedthrough the line 209 with 24 volt D.-C. positive. The terminals of theswitches 241 to 246 of the left hand device of the unit 94 are connecteddirectly with the 24 volt line 209 while the switches 247 through 252are connected through the relay 223 and a push button 253, which is theoff button, to the 24 volt D.-C..line. From this circuit it will beevident that pressure on the .olf button 253 will deactivate the righthand switches 247 through 252 of the unit 94; similarly energizing therelay 223 will deactive the right hand switches 247 through 252.

The off pushbutton 253 is a momentary-contact pushbutton which inaddition to the normally closed switch between the 24 volt negativeD.-C. line 210 and the coil of the relay 223 just described has anormally open switch between the line 210 and the coil of the relay 225in series with a resistor 254 for which I prefer a value of 100 ohms.The third switch, normally closed, of the pushbutton 253 connects theline 209 with a blade 256 and a blade 257 of the relay 223.

In addition to the off pushbutton 253 I have provided my circuit with anormally open, single-pole, interlock, momentary-contact pushbutton 258connecting the 24 volt negative D.-C. line with a red indicator lamp 259and a resistor 261 which I prefer to have a value of 250 ohms. Asingle-pole, momentary-contact, normally open, reduced pressurepushbutton 262 connects the coil of the relay 227 with a blade 263 ofthe relay 226, a blade 264 of the relay 1227 and a terminal 266respectively of a relay 225. Another single-pole, momentary-contact,

7 normally open normal pressure pushbutton 268 connects a terminal 269of the relay 223 and a blade 271 of the relay 225 with the coil of therelay 225 and with the resistor 254.

A single-pole, normally open, momentary-contact ""manual controlpushbutton 272 connects the positive D.-C. line 209 with the coil of therelay 223. A singlepole, normally open, momentary-contact resetpushbutton 273 connects the DC. positive line 209 with a blade 274 ofthe relay 235. A double-pole, momentarycontact signal reset pushbutton276 comprises a normally open switch between the negative D.-C. line 210and the line 277 connected as hereinafter described and a normallyclosed switch connecting the positive D.-C. line 209 with the line 278connected through diode 330 w'ithfblades 279, 281,282,283, 284, 285,286, 287,288,

289 respectively of the relays 211, 212, 213, 214, 215, 216, 217, 218,219 and 220. A doublepole, momentary-contact, lamp test pushbutton 291comprises a normally open switch connecting the 24 volt A.C. line 207with the normally closed terminals associated with the blades 349, 351,352, 353, 354, 356, 357, 366 and 367 of the relays 212, 213, 214, 216,217, 218, 219, 220 respectively, said blades being connected to the redalarm lamps 301, 302, 303, 304, 305, 306, 307, 308 and 309 and with theline 310 which line is connected with additional lamps as shallhereinafter be described. The pushbutton 291 also comprises a normallyopen switch connecting the negative D.-C. line 210 through the resistor261, to the red lamp 259 and the coil of the relay 228.

A timer indicated generally at 311 comprises a motordriven clock 312,solenoid 313 and switches 314, 316, 317 timed by the clock 312. For thetimer 311 I prefer to use the type TSA-18 catalogue Number 695 x 37 DualElectric Cycle Timer made by the General Electric Company. The operationof the switches 314, 316 and 317 in the timer 311 can be varied to suitthe conditions of the system. In one typical insulation I prefer to setthe timer 311 so that when the solenoid 313 is energized the switch 316closes for the full time cycle of 60 minutes, the switch 314 closes forfive minutes and then reopens and remains open for the duration of thecycle and the switch 317 remains open for approximately five and a halfminutes and then closes for the remainder of the cycle. Thus there is agap of approximately half a minute between the reopening of the switch314 and the closing of the switch 317. The length of the time cycle forthe switch 314 should be the experimentally determined time required tobring the remote end of the system up to pressure.

One terminal of the motor for the clock 312 and one terminal of thesolenoid 313 of the timer 311 is connected with the ground wire 204. Theother terminal of the motor for the clock 312 is connected with anormally open terminal associated with the blade 318 of the relay 234,and the other terminal of the solenoid 313 is connected with a terminal319 of the relay 234. The switch 314 connects the positive D.-C. line209 with the coil of the relay 224, the switch 317 connects the normallyopen terminal of the blade 318 of the relay 234 with one terminal of thehigh-voltage coil of a transformer-rectifier indicated as 321, and theswitch 316 connects the normally open terminal associated with the blade318 of the relay 234 to the normally open terminal associated with theblade 319 of the same relay.

The transformer-rectifier 3221 has its power coil connected across theA.-C. lines 203 and 204 through the switch 317 of the timer 31 1. Thetransformer-rectifier 321 supplies 24 volt 1).-C. having a commonnegative through the line 210 with the transformer-rectifier 206. The 24volt DHC. positive output from the transformerrecti-fier 321 passesthrough the auxiliary switch 14-1 of the motor starter 133 (FIG. '3) tothe coil of the relay 218. A capacitor 323 which I prefer to have arating of 500 microfarads is connected in parallel with the D.-C. outputof the transformer-rectifier 321.

A capacitor 324 which I prefer to have a rating of 500 microfarads oneach of four upper plates has a lower plate connected with the line 277and opposing plates connected with blades 326, 327, 328, 1329respectively of the relays 211, 212, 213, and 214. A capacitor 331 forwhich 'I prefer to use a unit identical with the capacitor 324 has oneplate connected with the line 277 and opposing plates connected toblades 332, 333, 334, 335 respectively of the relays 21-5, 216, 217 and21-8.

A lead 336 (FIG. 3) from the phase 128 of the main circuit breaker 113furnishes power to the A-C. line 203 and to the transformer-rectifier206 through a circuit breaker 337 and to a lighting circuit receptacle339 through a circuit breaker 338, and to'a'chart drive 340 of theunit94 (FIG. 1) through the circuit breaker 337.

The relays 211, 212, 213, 214, 21-5, 21-6, 217, 218, 220, 221, 222, 232,233, 234 and 236 all have one side of their coils connected directlywith the D.-C. negative line 210. The relay 211 has the other side ofits coil connected through the switch 122 with the -D.-C. positive line209, and the red signal lamp 343. The blade 341 of the relay 211 isconnected with the A.-C. line 207 and has one terminal connected througha 'line 342 to a red lamp 343 (FIG. 5b) and the lamp 299 with the \A.-C.line 208. The other terminal of the switch 341 of the relay 211 isconnected through the line 344 and the green lamp 345 (FIG. 5b) with theline 208.

The blade 326 along with the blades 327, 328, 329, \332, 333, 334 and335 are connected when their relays are deenergized through a resistor346, which I prefer to have a value of 27 ohms with the negative platesof the capacitors 32-4 and 331. The normally open termirials associatedwith the blade '326 and the blades 327, 328, 329, 332, 333, 334 and 3 35are connected through diodes with the positive D.-C. line 209.

A jumper 347 between the positive side of the coil of the relay 211 andthe normally open terminal associated with the blade 279 suppliescurrent to the coil once the relay has been energized holding the relayclosed until it is released by pressure on the pushbutton 276. Similarjumpers connect the coils and terminals of the relays 2 12, 213, 214,215, 216, 217, 218, 219 and 2 20.

The relay 212 is energized by the closing due to high pressure of aswitch 348 in the nitrogen pressure alarm 66 FIG. 1). Blades 3'49, 351,352, 353, 354, 356 and 3 57 respectively of the relays 212, 213, 214,215, 216, 217, 218 are connected through the respective red lamps 301,302, 303, 304, 305, 306 and 307 with the A.-C. line 208. The normallyopen terminals associated with these blades are connected to the A.-C.line 207. The relay 213 is energized by the closing due to low pressureof a switch 358 in the nitrogen pressure alarm 66. The relay 214 isenergized by closing of a switch 359 operated by the oil level alarm 47when the oil level rises to a preselected level in the tank 42. The coilof the relay 215 is energized by the closing of a switch 361 operated bythe oil level alarm 47 when the oil level drops below a preselectedlevel in the tank 42. The coils of the relays 216 and 217 arerespectively connected with the switches 243 and 24 4 in the left handdevice of the unit 94. A normally closed switch, hereinafter to bedescribed, of the relay 228 is in series with the switch 244. The coil22 the relay 218 is energized by the closing of the switch One terminalof the coil of the relay 219 is connected through a blade 3'62 and itsassociated normally closed terminal, of the relay 288 with the negativeD.-C. line 210 and the other terminal of the coil is connected throughthe normally open terminal associated with the blade 288 of the relay219 and the pushbutt-on 273 with the positive D.-C. line 209, thenormally open terminal associated with the blade 274 of the relay 235and with the contacts 237i of the receptacle 237, and the control 238/1of the receptacle 238. The coil of the relay 220 is connected throughthe switch 364 actuated by the thermostat 49 in the pump room to closewhen the temperature in the pump room exceeds a preselected level.Blades 366, 367 of the respective relays 219, 220 are connectedrespectively through the red lamps 308, 309 with the A.-C. line 208. Thenormally open terminals associated with the blades 366, 367 areconnected with the A.-C. line 207.

The coil of the relay 221 is connected between the negative plate of thecapacitors 324 and 331 'and the negative D.-C. supply line 210. Therelay 221 has blades 368, 369, 371 connected as follows: the blade 368is connected to the positive D.C. line 209, its associated normally openterminal is connected through a resistor 372 which I prefer to have avalue of 100 ohms to the negative plate of the capacitors'324 and 33 1.The blade 369 is connected with the A.-C. line 207 and its associatednormally open terminal is connected across a buzzer switch 373 and abuzzer 374 to the A.-C. line 208. The blade 369 has a parallelconnection with the terminal block 376 to make provision for a remotebell if desired. The blade 371 is connected with the positive D.-C. line209 and through its associated normally closed terminal and the resistor377 and diode 378 with one terminal of the coil of the relay 222. Theother terminal of the coil of the relay 222 is connected with thenegative D.-C. line 210 across the capacitor 379 for which I prefer arating of 1500 microfarads. I prefer the resistor 377 to have a value of27 ohms. In addition to the before mentioned blade 297 the relay 222 hasa blade 381 and a blade 382.

The three blades of the relay 222 are connected as follows: The blade297 is connected with the A.-C. line 207 and through its associatednormally closed terminal and a White lamp 380 to the A.-C. line 208. Theblades 381 and 3 82 and their associated open and closed terminals areall connected with a terminal block 3 83. The terminal block 383provides terminals 387 through which con nections can be made to remotealarms.

The receptacle 237 has its contact 2371: connected with the positiveterminals of the coil of the relay 212 and its contact 237 connectedwith the positive terminal of the coil of the relay 220. The contact237a is connected to the A.-C. line 207, the contact 237d is connectedwith the positive side of the coil of the relay 214 and the contact 2370is connected with the positive side of the coil of the relay 213. Thecontact 237 is connected with the positive terminal of the coil of therelay 216; the contact 237e is connected with the positive terminal ofthe coil of the relay 215 and the contact 237g is connected with thepositive terminal of the coil of the relay 217. The contact 237k isconnected with the A.-C. line 208; the contact 23711 is connected withthe positive side of the coil of the relay 218 and the contact 237i isconnected with the positive side of the coil of the relay 219.

The coil of the relay 223 is connected through the pushbuttons 272 and253 between the positive D.-C. line 209 and the negative D.-C. line 210.The normally open terminal associated with the blade 256 is connected tothe positive side of the coil of the relay 223. The normally closedterminal associated with the blade 257 is connected to the switches 248,247, 250, 249, 252 and 251 and to a blade 391 of the relay 224. Thenormally open terminal associated with the blade 257 is connected withthe positive side of the coil of the relay 233. A blade 392 of the relay223 is connected with the A.-C. line 207; its associated normally closedterminal is connected with a blade 393 of the relay 225 and itsassociated normally open terminal is connected through an amber lamp 394with the A.C. line 208 and through a diode or half-wave rectifier 395with the lamp test line 310. Diode as used in this application isunderstood to refer to half-wave rectifiers which may be any of aplurality of known types of such rectifiers.

The coil of the relay 224 is connected with the switch 248 and 314 onone side and the negative D.-C. line 210 on the other. Two of the bladesof the relay 224 are utilized. The aforementioned blade 391 is connectedthrough its associated normally open terminal to -a blade 397 of therelay 225. A blade 398 is connected with the switch 247 and through itsassociated normally open terminal to the positive side of the coil ofthe relay 224. The relay 225 has its coil connected between thepushbutton 268 and through the resistor 254 to a normally open terminalof the pushbutton 253 on one side and to a normally closed terminal ofthe pushbutton 253 on the other. Of the three blades 271, 397 and 393 ofthe relay 225 the blade 271 is connected to the pushbutton .268 and tothe terminal 269 of the relay 223; its associated normally closedterminal 266 is connected with the blade 263 of the relay 226 and theblade 264 of the relay 227 and, through the pushbutton 262, with thecoil of the relay 227; and its normally open terminal with the coil ofthe relay 234 and through a diode 399 to the positive side of the coilof the relay 225. The blade 397 is connected with the normally openterminal associated with the blade 391 of the relay 224 and itsassociated normally open terminal is connected with the coil of therelay 233. The blade 393 is connected with the normally closed terminalassociated with the blade 392 of the relay 223, its associated normallyclosed terminal is connected with a blade 401 of the relay 227 and itsassociated normally open terminal is connected with the A.-C. line 208through the amber lamp 402 and, through the diode 403 to the lamp testline 310.

The coil of the relay 226 is connected with the switch 250 on one sideand with the normally open terminal associated with the blade 406 of therelay 227, and with the coil of the relay 231 on the other. Two of theswitches of this relay are utilized. These are the switches having theblade 263 and a switch having a blade 404 connected with the blade 249and having a normally open associated terminal connected to the positiveside of the coil of the relay 226. A normally open terminal associatedwith the blade 263 is connected with the positive side of the coil ofthe relay 233. The coil of the relay 227 is connected on one side to thepushbutton 262 and on the other to the normally open terminal associatedwith the blade 414 of the relay 228. Of the blades of the relay 227 theblade 264 is connected with the pushbutton 262 and through itsassociated normally open terminal with the normally closed terminalassociated with a blade 407 of the relay 229 and to the positiveterminal of the coil 227. The blade 406 is connected through itsassociated normally open terminal with the negative side of the coils ofthe relays 226 and 231; and the blade 401 is connected through itsassociated normally closed terminal with the lamp 408 and through thediode 409 to the lamp test line 310. Through its associated normallyopen terminal the blade 401 is connected with the lamp 405 and with thediode 411 which, in turn, is connected with the lamp test line 310.

The coil of the relay 228 is connected on one side with the pushbutton258 and the resistor 261 and on the other side with the blade 407 of therelay 229 and with the contact 238a of the receptacle 238. The blade 362is connected through its associated normally open terminal to the coilof the relay 228. A blade 413 of the relay 228 is connected through theswitch 244 with the positive D.-C. line 209; its associated normallyclosed terminal is connected to the coil of the relay 217, and itsassociated normally open terminal is connected with the blade 415 of therelay 229. A blade 414 of the relay 228 is connected with the negativeD.-C. line 210 through the normally closed switch of the pushbutton 253;its associated normally closed terminal is connected with the positiveterminal of the coil of the relay 235 and its associated normally openterminal is connected with the coil of the relay 227.

The coil of the relay 229 is connected on one side through the switch246 with the D.-C. positive line 209 and to the normally open terminalassociated with the blade 415 of the relay 229, and also to the normallyclosed terminal associated with the contact 238e of the receptacle 238,and on the other side with the D.-C. negative line 210. Of the blades ofthe relay 229 the blade 407 is connected as hereinbefore described, ablade 417 is connected through the switch 142 of the motor starter 133(FIG. 3) with the A.-C. line 203. The normally open terminal associatedwith the blade 417 is connected through the coil of the magnetic valve79 with ground.

The relay 230 is a spare relay for which a receptacle is provided havingno connected wiring.

The positive terminal of the coil of the relay 231 is connected to theswitch 252 and the contact 238 of the receptacle 238 and the negativeterminal is connected to the normally open terminal associated with theblade 406 of the relay 227. Two of the blades of the relay 231 areoperative. A blade 418 is connected with the switch 251 and through itsassociated normally open terminal to the coil of the relay 231; and ablade 419 is connected with the A.-C. line 203. The normally openterminal associated with the blade 419 is connected through the coil ofthe magnetic valve 91 with ground.

The coil of the relay 232 is connected between the negative D.-C. line210 on one side and the switch 242 and the contact 238g of thereceptacle 238 on the other. A blade 421 of the relay 232 is connectedwith the switch 241 and its associated normally open terminal isconnected to the coil of the relay 232. A blade 422 of the relay 232 isconnected with the AC. line 203 and the blade 419 of the relay 231 andthe normally open terminal associated with the blade 422 is connectedthrough the coil of the magnetic valve 91 to ground.

The coil of the relay 233 is connected between the negative D.-C. line210 and the normally open terminals associated with the blades 257, 397and 263 respectively of the relays 223, 225 and 226. A blade 423 of therelay 233 is connected with the A.-C. line 207; its associated normallyclosed terminal is connected through a green lamp 424 with the A.-C.line 208 and through a diode 426 to the lamp-test line 310, and itsassociated normally open terminal is connected through a green lamp 427with the A.-C. line 208 and through a diode 428 with the lamptest line310. A blade 429 of the relay 233 is connected to the A.-C. line 203.The associated normally open terminal of the blade 429 is connectedthrough the coil 134 and overload switches 136 of the motor starter 133(FIG. 3) with ground. A blade 431 of the relay 233 is connected with theA.-C. line 203. The normally open terminal associated with the blade 431is connected to the blade 319 of the relay 234.

The relay 234 is connected between the negative D.-C. line 210 and thenormally open terminal associated with the blade 271 of the relay 225.The blade 318 of the relay 234 is connected with the D.-C. line 203, andits associated normally open terminal is connected with the motor 312 ofthe timer 311. The blade 319 of the relay 234 is connected through itsassociated normally open terminal to the solenoid 313 of the timer 311.

The coil of the relay 235 is connected between the normally closedterminal associated with the blade 414 of the relay 228 on one side; andthe switch 245, the normally open terminal associated with the blade 274of the relay 235, and the contact 23811 of the receptacle 238, on theother. The blade 274 of the relay 235 is connected as has beenhereinbefore described. A blade 433 of the relay 235 is connected withthe A.-C. line 203 and through its associated normally open terminal andthrough the coil of the magnetic valve 33 (FIG. 1) with the groundedline 204. A blade 434 of the relay 235 is connected through an amberlamp 436 to the A.-C. line 208. The normally closed terminal associatedwith the blade 434 is connected through the diode 435 to the lamp-testline 310. The normally open terminal associated with the blade 434 isconnected with the A.-C. line 207.

The coil of the relay 236 is connected between the negative D.-C. line210 on one side and, on the other side, through jumpers 436, 437, 438,439 and 441 in plug-in type connectors hereinafter to be described, tothe positive D.-C. line 209, and parallel to the said jumpers to thecontact 238i of the receptacle 238. The blade 442 of the relay 236 isconnected through a capacitor 443 which I prefer to have a value of 300microfarads and a resistor 444 which I prefer to have a value of 27 ohmsto the normally closed terminal associated with the blade 442. Theresistor 444 and the capacitor 443 in parallel are connected with thepositive terminal of the coil of the relay 225. The normally openterminal associated with the blade 442 is connected with the positiveD.-C. line 209. A blade 446 of the relay 236 is connected through thered lamp 436 to the A.-C. line 208 and through the diode 445 to thelamp-test line 310. Through its associated normally closed terminal theblade 446 is connected to the A.-C. line 207.

The contact 23812 of the receptacle 238 is connected with the positiveside of the coil of the relay 223, and the contact 238j is connectedwith the positive side of the coil of the relay 222. The contact 238::is connected with the positive D.-C. line 209; the contact 238d isconnected with the positive side of the coil of the relay 226, and thecontact 238e is connected with the positive terminal of the relay 224.The contact 238j is connected with the positive side of the coil of therelay 231; the contact 238e is connected to the positive side of thecoil of the relay 229 and the contact 238g is connected with thepositive side of the coil of the relay 232. The contact 238k isconnected with the negative D.-C. line 210; the contact 238h isconnected with the positive side of the coil of the relay 235 and thecontact 2381' is connected with the positive side of the coil of therelay 236.

A green lamp 447 is connected between the A.-C. lines 208 and 207 andthrough a diode 449 to the lamp-test line 310.

It is a feature of my invention that the relays 211-236 are connectedwith the operating elements of the controls and with the externalapparatus through plug-in type connectors, each comprising a receptacleand plug. Referring to FIG. 6 a relay panel 448 includes plug-in typereceptacles 451, 452, 453, 454, 456, 457 and 458 and their respectivemating plugs 459, 461, 462, 463, 464, 466 and 467. The plug-inconnectors 451 to 458 are of known types and are available fromcommercial sources.

The receptacle 451 andthe plug 459 together constitute a 15-pointconnector. The plug 459 is connected to an alarm panel 468 by a cable469. The panel 468 comprises the lamps 299, 301, 302, 303, 304, 305,306, 307, 308 and 309. The receptacle 452 and the plug 461 togetherconstitute a 27-point connector, the plug 461 being connected by a cable471 to a control panel 472 which comprises the push-buttons 276, 291,272, 268, 262, 253, 273, and 258 and the lamps 380, 385, 394, 402, 405,408, 436, 259, 343, 345, 424, 427, 447 and 396 (FIGS. 4a, 4b). Thereceptacle 53 and the plug 462 together constitute a 24-point connector.The plug 462 is con- .nected through a cable 473 to a terminal block474, which is, in turn wired to apparatus comprising the oil levelindicator alarm 47, the pump-room thermostat 49, the nitrogen pressureswitch 66. The terminal block 474 also provides 8 terminals 476 whichmay be connected to remote alarms if desired.

The receptacle 454 and the plug 463 together constitute a 6-pointconnector. The plug 463 is connected through a cable 477 to a terminalblock 478 which is, in turn, wired to the normally open magnetic reliefvalve 79, the normal-1y closed magnetic valve 91 to the A.-C. power line336 (FIG. 3) and to the grounding wire (or insulated neutral) 204. Itwill be understood that although I prefer to terminate the cables 473and 477 in the respective terminal blocks 474 and 478 I do not wish 13to be limited to this construction and other methods of connecting theplugs 473, 477 to their control elements either directly or indirectlymay be used.

The receptacle 456 and the plug 464 together constitute an 8-pointconnector, the plug 464 being connected through a cable 479 to theterminals of the timer 311.

The receptacle 457 and the plug 466 together constitute a ten-pointconnector. The plug 466 is connected through a cable 481 to a panel 482comprising the switches 122 and 126 of the relay 119 (FIG. 2), the coil134 of the motor starter 133, and the auxiliary switches 141, 142 of thestarter 133 (FIG. 3).

The receptacle 458 and the plug 467 together constitute a 21-pointconnector. The plug 467 is connected through a cable 483 to the panel484 for the recorder 94 comprising the switches 241, 242, 243, 244, 245,246, 2 47, 248, 249, 250, 251 and 252 and the chart drive 340.

The jumper 436 in the plug 459 is connected between two points 486 and487 in the connector. Point 487 of the receptacle 451 is connected bymeans of a wire 488 in the panel 448 to a point 489 in the receptacle453. The point 489 is connected by means of the jumper 437 in the plug462 to a point 491 in the connector comprising the plug 462 and thereceptacle 453. The point 491 is connected by means of a wire 492 in thepanel 448 to a point 493 in the receptacle 456. The point 493 isconnected by means of the jumper 438 in the plug 464 to a point 494 inthe plug 464. The point 494 is connected by means of a wire 496 in thepanel 448 to a point 497 in the receptacle 457. The point 497 isconnected by means of the jumper 43-9 in the plug 466 to a point 498 inthe plug 466. The point 498 is connected by means of a wire 499 in thepanel 448 to a point 501 in the receptacle 458. The point 501 isconnected through the jumper 441 in the plug 467 to a point 502 in theplug 467. The jumpers 436, 437, 438, 439, 441 and panel wires 488, 492,496, 499 are thus seen to form a series connection between the point 486and the point 502 which will be interrupted by the separation of any oneor more of the plugs 459, 462, 464, 466, or 467 from its matingreceptacle.

I have hereinbefore indicated that I prefer to use standard plug-in type'3-pole, double-throw relays for the re lay panel of my controller '11.I have found that although a plurality of said relays do not require theuse of all the terminals of the 3-pole, double-throw type the advantagesof standardization outweigh any hypothetical economy that might beachieved by using simple-r types of relays where they would sufiice. Oneadvantage, which will be immediately apparent, is that the spare relay230 may be quickly substituted for any of the other relays thatmalfunctions or becomes damaged. I have preferred to use I l-pin relayshaving S-a-mpere contacts and a 24 volt D.-C. 475 ohm coil such as therelays made by the Line Electric Company and sold under their number MKP3D34. The operation of the said relays is independent of the polarity ofthe coil connections.

I have provided two ll-point test receptacles 237 and 238. Thereceptacles 237 and 238 are not intended for the insertion of relays butfor the insertion respectively of an 11-point jack 601 having pins60*1a-601k and an 11- point jack 602 having pins 602a-602k (FIGS. 7 and8), said jacks comprising part of a test unit designated generally as603. The jacks 601 and 602 are connected to the test unit 603 by theirrespective cables 604 and 606. The cables 604 and 606 enter a housing607 upon which are mounted a D.-C. voltmeter 608 and its associatedpush-button 609, an A.-C. voltmeter 61 1 and its asso ciated push-button612, a relay test receptacle 613 having contacts 613a613k, and itsassociated push-button 614, red lamps 616, 617, 618 and green lamps 619,621, 622. Also mounted on the housing 607 are a plurality ofpush-buttons 623, 624, 626, 627, 628, 629, 631, 632, 633, 634, 636, 637,638, 639, 641, 642, 643, each having one terminal connected through thecable 606 to the pin 602a of the jack 602. The remaining terminals ofthe push-button are connected to the pins of the jacks 601 and 602 asfollows: 623 is connected to 601k; 624 is connected to 6010; 626 isconnected to 601d; 627 is connected to 601e; 628 is connected to 601 629is connected to 601g; 631 is connected to 601k; 632 is connected to601i; 633 is connected to 601 634 is connected to 60212; 636 isconnected to 6020; 637 is connected to 602d; 638 is connected to 602e;639 is connected to 602]; 641 is connected to 602g; 642 is connected to602k; 643 is connected to 602i. The pushbutton 609 is connected betweenthe pin 602a and the D.-C. voltmeter 608 and thence to the pin 602k. Thepushbutton 612 has one terminal connected to the pin 601a and also tothe contacts 613a, 613k and 613i and the other terminal connectedthrough the A.-C. voltmeter 611 to the pin 601k and each of the lamps616, 617, 618, 619, 621 and 62 2.

The relay test push-button 614 is connected between the pin 602a and thecontact 613b. Each of the lamps is connected to a contact of the testreceptacle 613 as follows: 616 is connected to 613d; 61-7 is connectedto 6132; 618 is connected to 613k; 619 is connected to 613a; 621 isconnected to 613g; 622 is connected to 6131'.

The jack 602 plugs into the receptacle 238, each of the pins of the jackfitting into a like lettered contact of the receptacle. Similarly thejack 601 plugs into the receptacle 237, each of the pins again fittinginto the contact having the same letter designation. The relays 2124 36,being identical, will each fit the receptacle 613 in such a manner thatwhen a relay is inserted the contacts 61Gb and 613 will be across thecoil, 613a will contact one blade, 6130 will contact the normally openterminal associated with the blade contacted by 613a, and 613d willcontact the normally closed terminal associated with said blade. Thecontact 6131 will connect to another of the blades of the relay, 613g tothe normally open terminal associated with said blade and 6132 to thenormally closed terminal associated with said blade. The contact 613kwill connect with the third blade of the relay, 613i with the normallyopen terminal associated with said blade and 613h with the normallyclosed terminal associated with said blade.

Operation To introduce oil into a newly installed pipe-type cable theentire system is first flushed out with dry nitrogen. A vacuum pump maythen be connected to the system by means of the normally closed manualvalve 701 (FIG. 1). I prefer to evacuate the entire system to a pressureof 1 mm. or less of mercury and to search out and repair any leaks untilthe system will show an increase of pressure less than 1 mm. of mercuryin one hour. Oil is then introduced into the system while stillmaintaining vacuum at the valve 701 until oil passes through the valve.The oil storage tank 42 has a volume adequate for the volumefluctuations of the system in operation but insufiicient to fill thesystem initially. I have therefore provided a normally closed manualauxiliary filling valve 702 through which the system can be filleddirectly from tank trucks. During the filling the pump 13 may beby-passed. If the pump 13 is operated to fill the pipe-type cable thecon trols may be set for manual or reduced pressure operation during thefilling operation. During reduced pressure operation the pump will stopwhen the pressure reaches a value which I prefer to set at 65 p.s.i.g.

With the system still under vacuum and the valves 41 and 46 open, oilwill enter the oil storage tank 42. When a sufficient supply of oil hasentered the tank 42 leaving enough volume in the tank to accommodate theoil that will be forced from the pipe-type cable when the latter isenergized with a consequent increase in temperature the valve 46 (and46a for a 2-controller system) is closed and the remainder of the tank42 filled with dry nitrogen from the cylinder 50.

The system having been filled with oil the valves 701 and 702 areclosed, the valve 46 (and 46a) opened and the system maintained atreduced pressure until the cable system is ready to be tested and/orenergized. When the system is ready to go from reduced pressure ontonormal pressure operation it is only necessary to depress the normalpressure push-button 268 (FIG. a) momentarily energizing the coil of therelay 225. Energizing of the coil of the relay 225 will move the blade271 to its normally open terminal and continue to feed current to thecoil so long as the blade 256 of the relay 223 is in its normally closedposition. If, however, the manual push-button 272 has been depressed andthe relay 223 is locked in its energized position no current will feedinto the blade 271. In this situation it is first necessary 'to depressthe off push-button 253 and open'the cir-' cuit supplying current to theblade 256 of the relay 223 so as to deenergize the coil of that relay.When the system is in normal condition with the relay 225 energized, theblade 393 will have closed the circuit to light the amber lamp 402.Consider the case where the system is in normal operation there isadequate pressure in the pipe-type cable and the pump is not running.The coil 134 (FIGS. 3 and 5b) of the motor starter 133 will bedeenergized. When, because of a decrease in the ambient temperature orin the load in the cable the oil cools somewhat and the pressure in thepiping 96 (FIG. '1) drops below 200 p.s.i.g. the switch 246 in the unit94 will close energizing the coil of the relay 229 whereby the blade 417will move to its normally open terminal and close the magnetic reliefvalve 79 so long as the pump is inoperative. When the coil 134 for themotor starter 133 is energized the auxiliary switch 142 will open thecircuit through the magnetic valve 79. Closing of the valve 79 willprevent any oil from leaving the pipetype cable and returning to thestorage tank 42. As cooling continues and the pressure in the line 96drops to 180 p.s.i.g. the switch 248 will close and energize the coil ofthe relay 224 (so long as the relay 223 which is responsive to themanual push-button 272 is in its deenergized position). Under theseconditions the switch 247 which closes at a pressure of 210 p.s.i.g.will be closed locking the relay until the pressure rises above 210p.s.i.g. With the coil of the relay 224 energized the blade 391 will bein contact with its normally open terminal and current will pass fromthe positive D.-C. line 209 through the push-button 253, the blade 257of the relay 223, the blade 391, the blade 397 of the relay 225 which isenergized when the system is at normal pressure operation, to energizethe coil of the relay 233 thus moving the blade 429 to close the circuitthrough the motor starter coil 134, starting the pump 13. At the sametime the blade 423 will move to extinguish the green lamp 424 and lightthe green lamp 427.

During normal pressure operation the coil of the relay 234 will beenergized through the blade 271 of the relay 225. The blades 318 and 319of the relay 234 will be in contact with their respective normally openterminals in the circuits supplying current to the motor 312 andsolenoid 313 of the timer 311.

The blade 318 is connected to the A.-C. line 203 so that when the systemis in normal pressure operation resulting in the relay 234 beingenergized the clock motor 312 of the timer 311 will be in operation. Theblade 319 is connected to the normally open terminal of the blade 431 ofthe relay 233 so that when the pump starts during normal operation thesolenoid 313 will start a time cycle. Since the relay 234 is notenergized during manual and reduced pressure operation the timer willnot start under those conditions even though the pump is activated. Ashas been hereinbefore stated, when a time cycle starts the switch 314will close for a period (typically 5 minutes) sufiicient for pressure toreach the remote end of the pipetype cable. The switch 314 bypasses theswitch 248 energizing the coil of the relay 224 for a five-minute periodeven though the switch 247 should open due to the pressure in the piping96 exceeding a value of 210 p.s.i.g. Adequate pressure is thus assuredthroughout the entire length of the system. At the termination of aperiod which I prefer shall be /2 minute after the reopening of theswitch 314 the timer 311 will automatically close the switch 317 in theprimary circuit of the transformerrectifier 321 (FIG. 4b). If, at orduring the time the switch 317 is closed, both the relays 233 and 234are energized (indicating that the pump is operating under normalpressure conditions) and the auxiliary switch 141 (FIG. 3) of the motorstarter 133 is closed the transformer-rectifier 321 will energize therelay 218, lighting the red lamp 307 through the blade 357 and throughthe blade 355 energizing the coil of the relay 221 (FIG.

'4b)"which closes the circuits to optionalrernote alarms connected tothe terminal block 383. Since the switch 317 of the timer 311 willremain closed for a chosen period such as 4% minutes starting of thepump due to loss of pressure during this period will cause an excessivecycling signal. By this means I am able to give an alarm for slow leakswhich are not sufiicient to cause a drop in pressure exceeding thecapacity of the pump. The timer 311 can be reset manually at any timeduring any part of its cycle by depressing the ofl push-button 253followed by depressing the normal pressure pushbutton 268. Since analarm will be given if the pump is operating under normal operationcondition at the same time as the timer switch 317 is closed, my methodof wiring will provide a warning for both the case where the pumprequires excessive time to bring the system up to pressure, and the casewhere the pump restarts too soon after having brought the system topressure. This latter warning will be given by virture of the fact,heretofore noted, that the switch 317 will remain closed for 60 minutesfrom the time the pump is started.

Should the pressure drop to p.s.i.g. in the line 96 the switch 244 willclose connecting the blade 413 of the relay 228 with the positive D.-C.line 209. If the system is operating at reduced pressure the coil of therelay 228 will be energized and the blade 413 will be in electricalconnection with the blade 415 of the relay 229 and closure of the switch244 will have no eifect except as a second source of current to keep thecoil of the relay 229 energized. Under normal pressure operation,however, the relay 228 will be deenergized and the blade 413 will beconnected with the coil of the relay 217. Closing of the switch 244under normal pressure conditions will thus energize the relay 217,lighting the red lamp 306 by means of the blade 356 and energizing thecoil of the relay 221 by means of the blade 334 and capacitor 331. Therelay 221 will sound a buzzer 374 and energize the terminal block 376which may be connected with a remote bell or bells and will alsodeenergize the coil of the relay 222 lighting the white lamps 380 and,by means of the blades 381 and 382, activating the remote alarmsconnected to the terminal block 383.

When, instead of a loss of pressure, the pressure in the pipe-type cablerises due to an increase in temperature at a time when the system is innormal pressure operation the valve 79 will open due to opening of theswitch 246 and the relay 229 when the pressure reaches 200 p.s.i.g.; thepump will stop due to opening the switch 247 and deenergizing the relays224 and 233 when the pressure reaches 210 p.s.i.g. provided it has notbeen stopped already by the timer 311. When the pressure rises to 225p.s.i.g. the mechanical relief valve 81 will open and oil will then flowback into the tank 42 through the pipe 14, valve 16, cross coupling 18,valve 17, T 24, union 22, valve 27, pipe 26, Ts 23, 74, 76, 77, strainer78, valves 79, 81 and 82, Ts 83, 84, 86, valve 87, union 21, pipe 38,valve 41, T 43 and the valve 46. When the pressure reaches 250 p.s.ig,the valve 88 will open providing a parallel return through the valve 89and the switch 241 Will c108 At 260 p.s.i.g. the switch 243 (FIG. 4a)

will close energizing the coil of the relay 216 which will light the redlamp 305 and through the relays 221 and 222 as hereinbefore described,sound the buzzer 374 and the remote alarms and light the lamp 380. Ifthe pressure continues to rise to 300 p.s.i.g. the switch 242 willclose, energizing the coil of the relay 232 which will remain energizeduntil the switch 241 opens again at 250 p.s.i.g. The relay 232 will openthe valve 91 by means of the blade 422. This will provide anotherparallel oil channel through the check valve 92 and valve 93 for thereturn of oil to the tank 42. Finally the safety valve 95 in the pump 13will relieve at 375 p.s.i.g., and should the reservoir 42 start to buildup pressure, a safety disk 703 therein will rupture at a pressure of 60p.s.i.g.

A feature accounting in part for the close limits within which I am ableto maintain the oil pressure on a pipe-type cable system resides in therelationship of the valves 81, 79 and 88 of which, as has been describedheretofore, the valve 81 is a mechanical valve which opens into thevalve 82 when the pressure behind it exceeds 225 p.s.i.g., the valve 88is a mechanical valve which opens into the valve 89 when the pressurebehind it exceeds 250 p.s.i.g. and the valve 79 is a magnetic valveoperated by means of the switch 246 and the relay 229 to close when thepressure drops below 200 p.si.g. Of the manual valves 90, 82 and 89 thevalves 82 and 89 are normally open and the valve 90 is normally closed.Under normal pressure operation no oil will pass through the valvesystem comprising the valves 81, 79 and 88 until the pressure has builtup to 225 p.s.i.g. At this point the valve 81 will open relieving thepressure in the line in a manner that has already been described. Sinceoil is practically an incompressible medium the pressure will drop veryquickly when the valve 31 opens and I have found that although, ideally,the valve 81 should close again as soon as the pressure drops below 225p.s.i.g. actual commercial mechanical relief valves have a considerabletime lag before they seat properly. I have found this particularly to bethe case when there was a considerable flow of oil through them.

In the instant case, however, as soon as the pressure drops to 200p.s.i.g. the magnetic valve 79 closes and permits the mechanical valve81 to lock into place. The valve 88 provides a safety relief which willopen in the event of malfunctioning that closes the valve 79 or fails toopen the valve 81 even at elevated pressure.

In the event that the temperature should rise excessively in the pumproom the switch 364 in the thermostat 49 (FIG. 1 will close, energizingthe coil of the relay 220 and lighting the red lamp 309. A high-lowcontrol 47 on the reservoir 42 comprises the switches 359 and 361.Should the oil level drop too low the switch 361 will close energizingthe relay 215 to light the red lamp 304 and energize the relay 221 tolight the white lamp 330 and sound the buzzer 374 and the remote alarms.A high oil level will act similarly through the switch 359 and the relay214 except that it will light the red lamp 303. The nitrogen control 66has switches 348 and 353. Should the pressure drop below a selectedvalue such as 2 p.s.i.g. the switch 358 will close and energize the coilof the relay 213 lighting the red lamp 302. Should the pressure riseabove some value such as p.s.i.g., the switch 348 will close to energizethe relay 212 and light the red lamp 301. In either event the relay 221will be energized, lighting the white lamp 380 and sounding the buzzer374 and the remote alarms.

I prefer to have two independent 3-phase sources of power supply, anormal supply 111 (FIG. 2) and an emergency supply 112. The powertransfer switches 114 and 117 for these sources are mechanicallyinterlocked by a mechanism 115 of known construction for which I make noclaim of invention. The mechanism 115 is so constructed that either orboth of the circuit breakers 114 and 117 may be open simultaneously;either the circuit breaker 114 or the circuit breaker 117 may be closed;but

both the circuit breakers 114 and 117 cannot be closed simultaneously.If there is power in the normal supply 111 current will flow from thephases 127 and 128 to energize the coil 121 of the relay 119 closing theswitches 124 and 126 and opening the switches 122 and 123. With theswitch 124 closed the relay 116 will be energized to close the switch114 supplying current to the lines 113. In the event of failure of thenormal source 111 the coil 121 will be cleenergized and the switches 124and 126 will open and the switches 122 and 123 will close. Closing ofthe switch 123 will energize the coil 118 of the circuit breaker 117from the phases 131 and 132 thus closing the switch 117 to supply thepower lines 113. Return of power to the source 111 will energize thecoil 121 thus closing the switch 114. Due to the mechanized interlockthe switch 117 will then open.

When, due to loss of power at the source 111 the switch 122 closes andenergizes the coil of the relay 211 (FIG. 4a), note that in FIG. 4a therelay 211 is deenergized even though the switch 122 is closed. This isdue to the fact that the condition of the system in the drawings is onewhere the entire system is deenergized. The relay 211 will light the redlamps 299 and 343 and energize the coil of the relay 221 to sound thebuzzer and give the remote alarms. Each of the alarm relays 211, 212,213, 214, 215, 216, 217 and 218 locks in its closed position by means ofcurrent received through the right hand contact of the signal resetpushbutton 276 and will be deenergized when the pushbutton 276 isdepressed. Depression of the pushbutton 276 will also, through its lefthand contact, discharge the capacitors 324 and 331 and deenergize therelay 221. It is a feature of my invention that the coil of the relay222 is connected in parallel with the capacitor 379 and in series withthe resistor 377. Due to a finite length of time, which is about 5seconds using my preferred components, required to discharge thecapacitor, the relay 222 will remain energized during momentary currentinterruptions and will not give a remote alarm. If this delay featurewere omitted from my invention a trouble-shooter might journey aconsiderable distance to the controller from a remote alarm stationunnecessarily.

When the system utilizes both the controllers Hand 11:: I have foundthat it is convenient to have the normal power supply 111 for thecontroller 11 constitute the emergency power supply for the controfler11a and to have the emergency power supply 112 for the controller 11constitute the normal power supply for the controller 11a. In thismanner both power sources will be utilized during normal operation andwill be kept under the surveillance of the alarm system and yet thesystem will have the safeguard of a secondary power source. When twocontrollers are utilized either pump can be made to supply pressure forthe alternate side of the system by means of the normally closedmagnetic crossover valves 33 and 34. Consider the controller 11 with theunderstanding that an analogous discussion will apply to the controller11a. Should the pressure in the system, as reflected by the pressure inthe piping 96, drop to p.s.i.g. the switch 245 in the recorder 94 willclose, energizing the coil of the relay 235 to light the amber lamp 436and open the magnetic valve 33. With the valve 33 open oil will flowfrom the union 23a through the valves 37, 33, 31 and 36 into the lowpressure system. When the pressure in the piping 132a is reduced top.s.i.g. the pump 13a will start in a manner analogous to thathereinbefore described for starting the pump 13. In order for the relay235 to remain energized current must be supplied to the line connectedto the normally open terminal associated with the blade 274. Suchcurrent will be received through the blade 288 of the relay 219 whenthat relay is energized. The relay 219 is energized at the same time asthe relay 235 when the switch 245 closes provided the relay 228 which isenergized during reduced pressure operation is in the deenergized con-19 dition with its blade 362 in its normally closed position. Thisinterlock of relays prevents oil from draining from the controller 11ato the controller 11 when the latter is operating at reduced pressure.When the relay 219 is energized by closure of the switch 245 the redlamp 308 .Will be lighted by means of the blade 366.

When there is a leak in the pipe-type cable system suf- .ficiently largeto require deenergizing of the cable system it is desirable to reducethe oil pressure in the system to reduce oil losses through the leak.The pressure in the line can be reduced by depressing the off pushbutton253, and then simultaneously depressing the reduced pressure interlocpushbutton 258 and the reduced pressure pushbutton 262. This requiredsequence provides a safety measure so that only a person who is familiarwith the proper sequence will be capable of putting the pump on reducedpressure. Depressing the off pushbutton 253 when the system is operatingat normal pressure will break the circuit to the coil of the relay 225which has hereinbefore been shown to control the normal pressureoperation in response to the pushbutton 268. As a further precaution,when the off pushbutton 253 is depressed the positive terminal of thecoil of the relay 225 is connected through the resistor 254 to thenegative D.-C. line 210. Subsequent depression of the reduced pressureinterlock pushbutton 258 will close the circuit to the coil of the relay228 provided the relay 229 is energized which will be the case wheneverthe pressure has dropped to 200 p.s.i.g. due to the action of the switch246 as hereinbefore described. Should the relay 229 be deenergized, thecircuit to the coil of the relay 228 instead of passing to the blade 407directly from the positive D.-C. line 209 will follow the circuit formedby the blade 407, the normally open terminal associated with the blade264 of the relay 227, the pushbutton 262, the terminal 266 and blade 271of the relay 225, the terminal 269 and blade 256 of the relay 223, anormally closed contact of the pushbutton 253 and the D.-C. line 209.Simultaneous depression of the pushbuttons 258 and 262 will haveenergized the coil of the relay 227 which through the means of the blade406 will energize the coil of the relay 231 and open the magnetic reliefvalve 91 (FIGS. 1 and 5b) by means of the blade 419.

With the valve 91 open the oil pressure will quickly drop to 200p.s.i.g. at which point the valve 91 will close, as hereinbeforedescribed, to energize the relay 229 and connect the blade 407 directlyto the DC. line 209. While the system is operating at reduced pressurethe coil of the relay 23-3 controlling the pump motor will be in thecircuit including the blade 263 of the relay 226 which will start thepump when the pressure drops to 45 p.s.i.g. closing the switch 250 andstop the pump when the pressure increases to 65 p.s.i.g. Once the systemis operating regularly at reduced pressure the valve 91 will close underthe influence of the switch 251 acting through the relay 231 when thepressure drops to 60 p.s.i.g. and remain closed, unless for some reasonsuch as an increase in oil temperature, the pressure should rise to 75p.s.i.g. under which circumstance the switch 252 would close andenergize the coil of the relay 231. -While the controller 11 isoperating under reduced pressure the blade 414 of the relay 228 willopen the circuit to the coil of the relay 235 controlling the valve 33thus assuring that the valve 33 will remain closed and not drain oilfrom the controller 11a. The blade 413 of the relay 228 will also haveopened the circuit of the coil to the relay 217 so that no remote alarmwill be given due to closing of the oil pressure alarm switch 244.

As a safety measure preventing the inadvertent return to normal pressure1 have provided that it shall be necessary to push the manual pushbutton272 to return the system from reduced pressure to normal pressureoperation. The manual pushbutton 272 operates as follows: Depression ofthe manual pushbutton 272 energizes the coil of the 20 relay 223 whichautomatically locks in. by means of the blade 256. With the relay 223energized the normal pressure pushbutton 268 and the reduced pressurepushbutton 262 will be inoperative since they are in a series circuitwith the normally closed terminal 269 of the blade 256. The switches248, 247, 250, 249, 25-2, 251 are all connected through the normallyclosed terminal associated with the blade 257 to the line 209 and areinoperative when the blade 25-7 is connected to its normally openterminal. When the relay 223 is energized the blade 257 will connectwith the coil of the relay 233 starting the pump 13. Movement of theblade 392 when the relay 223 is energized serves to extinguish the redlamp 408 and light the amber lamp 394. With the pump 13 operating undermanual control the pressure will build up to 200 p.s.i.g. at which pointthe switch 246 will open and de-energize the relay 229. The blade 407will then move to its normally closed position but with the blade inthis position the circuit to the coil of the relay 228 will be stillopen because this circuit includes the blade 25 6 and terminal 269 ofthe relay 223.

It is a feature of my invention that the lamps can all be tested at onceby the simple depression of a pushbutton without interrupting normaloperation or setting off any false alarms. For this purpose I haveprovided a lamp test pushbutton 291 connected to the A.-C. line 207. Thelamps 299, 301, 302, 303, 304, 305, 306, 307, 308, 309 are eachconnected to a blade of a relay each of which blade has one associatedterminal connected with the lamp test pushbutton 291 and its otherassociated terminal connected directly to the A.-C. supply. Thus whenthe pushbutton 291 is depressed all the above mentioned lamps should belit either directly or through the pushbutton. The remainder of thepanel lamps with the exception of the red lamp 259 are connected throughindividual diodes that prevent the A.-C. current, used to supply any onelamp during normal operation, from lighting any of the others throughthe test circuit. The red lamp 259 is connected through the pushbutton291 between the negative D.-C. line 210 and the positive D.-C. line 209.

It is an advantage of my invention that the lamps associated with mycontrol circuit, such as the lamp 394, can be tested by the depressionof the pushbutton 29 1 but are not affected by the current feeding intoother lamps on the same circuit. In the case of the lamp 394, forexample, the lamp 402 might be lighted by the energizing of the relay225 whereby the blade 393 would close the circuit comprising the A.-C.line 207, the blade 392 of the relay 223, the blade 393 of the relay225, the lamp 402 and the A.-C. line 208, without lighting the lamp 394because of the diodes 395 and 403.

I have provided that in the event of a complete power outage involvingboth the normal and emergency power sources the system willautomatically return to normal pressure operation when power is restoredprovided it was operating at normal pressure at the time of the powerinterruption. I accomplish this objective in the following manner: Thepositive terminal of the coil of the relay 225 is connected to one plateof the capacitor 243. When power is resumed the relay 236 is energizedand the blade 442 becomes connected to the positive D.-C. line. Currentcan then pass through the coil of the relay 225 to charge the condenser443 thereby energizing the coil 22 5 in a manner analogous to depressingthe normal pressure pushbutton 268.

An important novel feature of my invention is provided by the testreceptacles 237 and 238 and the test unit 607 (FIGS. 7 and 8). Themethod of operating this unit is as follows: The jack 601 is inserted inthe receptacle 237 and the jack 602 is inserted in the receptacle 238.The test button 612 is then depressed with the result that the A.-C.voltmeter 611 will indicate the voltage across the low voltage A.-C.lines 207 and 208. The test button 609 is then depressed to indicate onthe D.-C. voltmeter 608 the voltage across the D.-C. lines 209 and 210.

When the jack 602 is inserted in the receptacle 238 the 21 jumper 605serves to short the positive lead to the coil of the relay 222 to thepositive line 209 thus keeping the relay 222 energized and preventing aremote alarm while the relays are undergoing test.

With the jacks 601 and 602 inserted, depression of the pushbutton 623will energize the coil to the relay 212 and, if said relay and itsassociated circuit is operating properly, light the lamp 301. The relay212 should then be deenergized by depressing the signal reset pushbutton276. Similarly, depression of the pushbuttons 624, 626, 627, 628, 629,631, 632 and 633 will test the relays 213, 214, 215, 216, 217, 218, 219and 220 and their associated circuits, by respectively lighting thelamps 302, 303, 304, 305, 306, 307, 308 and 309. The relay 223 and itsassociated circuit is tested by depressing the pushbutton 634 to lightthe lamp 394. To test the relays 224 and 225 and their associatedcircuitry, the pushbutton 268 is first depressed, following which,depression of the pushbutton 636 will start the pump motor. The relays226, 227 and 228 and their associated circuits are tested by depressingthe reduced pressure interlock pushbutton 258 and the reduced pressurepushbutton 262 following which, depression of the pushbutton 637 willstart the motor. It will be understood that in testing the relays 223,224, 225, 226, 227 and 228 it is first necessary to depress the offpushbutton 253 to clear the controls. Prior to testing the relays 226 or231 the valve 17 should be closed to prevent loss of pressure in thesystem while the cable is energized. The relay 229 and the valve 79 andtheir associated circuitry are tested by depressing the pushbutton 638which has the effect of seating the valve. The relay 231 and the valve91 and their associated circuitry are tested by depressing thepushbutton 639, and similarly the relay 232 will close the valve 91 whenthe pushbutton 641 is depressed. The relay 235 and the valve 33 andtheir associated circuits are tested by depressing the pushbutton 642.To test the relay 236 and its associated circuit by lighting the lamp396, the plug 459 should be removed from the receptacle 451 followingwhich the pushbutton 643 should be depressed. All the relays can befurther tested by inserting them in the test receptacle 613. When arelay is inserted in the receptacle 613, A.-C. current is supplied toeach of the three blades of the relay through the contacts 613a, 613kand 613i and the lamps 616, 617, 618 which are connected to the normallyclosed terminals will light. When the relay test button 614 is depressedD.-C. voltage will be impressed across the coil of the relay beingtested through the contacts 61% and 6131', moving the blades to lightthe lamps 619, 621, 622 and extinguish the lamps 616, 617 and 618.

I claim:

1. Apparatus for controlling the oil pressure in an electric cablecomprising an A.-C. bus, a D.-C. bus, a plurality of magnetic relaysenergizable across said D.-C. bus, sensing means for sensing theconditions of said cable, said relays being responsive to said sensingmeans, a plurality of signal lamps energizable across said A.-C. bus bymeans of said relays, electric circuitry associated with each of saidrelays, at least one receptacle comprising a plurality of contacts, twoof said contacts being electrically connected across said A.-C. bus,another two of said contacts being electrically connected across saidD.-C. bus, a plurality of said contacts each being electricallyconnected to one of said relays, testing means comprising an A.-C.voltmeter connected to engage the contacts across said A.-C. bus, a DC.voltmeter connected to engage the contacts across said D.-C. bus, andswitching means for energizing each of said relays and its associatedcircuitry across said D.-C. bus, whereby the voltage across said A.-C.bus and the voltage across said D.-C. bus may be tested and each of saidrelays and its associated circuitry may be tested without being removedfrom said apparatus.

Cir

2. Apparatus for controlling the oil pressure in an electric cablecomprising an A.-C. bus, a D.-C. bus, at plurality of interchangeable,plug-in type magnetic relays, each having a plurality of pins,energizable across said D.-C. bus, sensing means for sensing theconditions of said cable, said relays being responsive to said sensingmeans, a plurality of signal lamps energizable across said A.-C. bus bymeans of said relays, electric circuitry associated with each of saidrelays, at least one receptacle, said receptacle comprising a pluralityof contacts, a first two of said contacts being electrically connectedacross said A.-C. bus, a second two of said contacts being connectedacross said D.-C. bus, a plurality of the remainder of said contactseach being connected to one of said relays, a test unit comprising ahousing, an A.-C. voltmeter mounted in said housing, pins electricallyconnected across said voltmeter matching said first tWo of said contacts for testing the voltage across said A.-C. bus, a D.-C. voltmetermounted in said housing, pins electrically connected across said D.-C.voltmeter matching said second two of said contacts for testing thevoltage across said D.-C. bus, a test receptacle mounted in saidhousing, said test receptacle matching said relays and comprising aplurality of test contacts, a plurality of test lamps each beingconnected to one of said test contacts whereby said relays may be testedafter being inserted in said test receptacle, a first multipin jackmatching said first recep tacle, a second multipin jack matching saidsecond receptacle, a first cable connecting said first jack to saidhousing, a second cable connecting said second jack to said housing, aplurality of push-buttons mounted on said housing, said push-buttonsbeing so connected that when said first and second jack are respectivelyinserted in said first and second receptacle the depression of each ofsaid pushbuttons will energize a diiferent one of said relays by meansof current from one of said buses, whereby said relays and theirassociated circuitry may be tested without removing said relays fromsaid apparatus.

3. Apparatus for controlling oil pressure in an electric cablecomprising a plurality of sensing means, a plurality of operating means,a plurality of signal means, and a remote alarm means, a plurality ofmagnetic relays interconnected with said sensing, operating, and signalmeans, at least one of said sensing means energizing both said signalmeans and said remote alarm means simultaneously, at least onereceptacle having a plurality of contacts electrically connected to saidrelays, a multipin jack electrically connected to a plurality ofpushbuttons, said jack fitting said receptacle, the operation of saidpushbuttons serving to test said relays, said jack being inserted insaid receptacle, and means, operated automatically by the insertion ofsaid jack, preventing the energizing of said alarm means during thetesting of said relays.

References Cited by the Examiner UNITED STATES PATENTS 1,111,362 9/1914Carrigan.

2,127,343 8/1938 Parlett.

2,309,174 1/ 1943 Dodd 340-213 2,377,569 6/ 1945 Morse 3402l3 2,566,3679/1951 Peters 340-214 2,576,892 11/1951 Stanton.

2,625,597 1/1953 Dodd 340256 2,685,684 8/1954 Atkinson et a1 3402562,697,824 12/1954 Norton et a1 340-214 2,73 6,004 2/1956 Greene 340214 X2,839,741 6/ 1958 Kratville 340-214 2,93 0,031 3/ 1960 Ungar 340-2403,025,504 3/ 1962 Ohse 340240 3,040,243 6/1962 Weiss.

3,159,747 12/1964 Jones 340-214 X NEIL C. READ, Primary Examiner.

R. M. ANGUS, D. YUSKO, Assistant Examiners.

1. APPARATUS FOR CONTROLLING THE OIL PRESSURE IN AN ELECTRIC CABLECOMPRISING AN A.-C. BUS, A D.-C. BUS, A PLURALITY OF MAGNETIC RELAYSENERGIZABLE ACROSS SAID D.-C. BUS, SENSING MEANS FOR SENSING THECONDITIONS OF SAID CABLE, SAID RELAYS BEING RESPONSIVE TO SAID SENSINGMEANS, A PLURALITY OF SIGNAL LAMPS ENERGIZABLE ACROSS SAID A,-C. BUS BYMEANS OF SAID RELAYS, ELECTRIC CIRCUITRY ASSOCIATED WITH EACH OF SAIDRELAYS, AT LEAST ONE RECEPTACLE COMPRISING A PLURALITY OF CONTACTS, TWOOF SAID CONTACTS BEING ELECTRICALLY CONNECTED ACROSS SAID A.-C. BUS,ANOTHER TWO OF SAID CONTACTS BEING ELECTRICALLY CONNECTED ACROSS SAIDD.-C. BUS, A PLURALTIY OF SAID CONTACTS EACH BEING ELECTRICALLYCONNECTED TO ONE OF SAID RELAYS, TESTING MEANS COMPRISING AN A.-C.VOLTMETER CONNECTED TO ENGAGE THE CONTACTS ACROSS SAID A.-C. BUS, AD.-C. VOLTMETER CON-